[PATCH 2/2] cmd/mmc: add subcommand to query max enhanced partition size

[Matthias Schiffer]

From: Markus Niebel <Markus.Niebel at ew.tq-group.com>

The new command prints the sector count and size in a human-readable
format and sets an environment variable for scripted handling. The
variable value is set in decimal to match what the 'mmc hwpartition'
command expects.

The environment variable can be used for automated partitioning scripts,
for example the following would convert a whole eMMC to pSLC mode:

    mmc maxhwpartsectors
    mmc hwpartition user enh 0 ${maxhwpartsectors} wrrel on complete

Signed-off-by: Markus Niebel <Markus.Niebel at ew.tq-group.com>
Signed-off-by: Matthias Schiffer <matthias.schiffer at ew.tq-group.com>
---

The human-readable output of the command could also be added to `mmc info`,
but it would still be great to have a separate command that sets an
environment variable for scripting, like this patch adds.


 cmd/mmc.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/cmd/mmc.c b/cmd/mmc.c
index f1e30d0cf64..d0b33cc0494 100644
--- a/cmd/mmc.c
+++ b/cmd/mmc.c
@@ -593,6 +593,33 @@ static int do_mmc_list(struct cmd_tbl *cmdtp, int flag,
 }
 
 #if CONFIG_IS_ENABLED(MMC_HW_PARTITIONING)
+static int do_mmc_maxhwpartsectors(struct cmd_tbl *cmdtp, int flag, int argc, char * const argv[])
+{
+	struct mmc *mmc;
+	u64 sectors;
+
+	mmc = init_mmc_device(curr_device, false);
+	if (!mmc)
+		return CMD_RET_FAILURE;
+
+	if (mmc_max_enhanced_size_sectors(mmc, &sectors))
+		return CMD_RET_FAILURE;
+
+	/* Ensure that the value fits in mmc_hwpart_conf::user.enh_size */
+	if (sectors > UINT_MAX) {
+		puts("ERROR: sector count larger than UINT_MAX\n");
+		return CMD_RET_FAILURE;
+	}
+
+	env_set_ulong("maxhwpartsectors", sectors);
+
+	printf("Maximum size of hardware partition: %u sectors (",
+	       (uint)sectors);
+	print_size(sectors * 512, ")\n");
+
+	return 0;
+}
+
 static int parse_hwpart_user(struct mmc_hwpart_conf *pconf,
 			     int argc, char *const argv[])
 {
@@ -1021,6 +1048,7 @@ static struct cmd_tbl cmd_mmc[] = {
 	U_BOOT_CMD_MKENT(dev, 4, 0, do_mmc_dev, "", ""),
 	U_BOOT_CMD_MKENT(list, 1, 1, do_mmc_list, "", ""),
 #if CONFIG_IS_ENABLED(MMC_HW_PARTITIONING)
+	U_BOOT_CMD_MKENT(maxhwpartsectors, 1, 0, do_mmc_maxhwpartsectors, "", ""),
 	U_BOOT_CMD_MKENT(hwpartition, 28, 0, do_mmc_hwpartition, "", ""),
 #endif
 #ifdef CONFIG_SUPPORT_EMMC_BOOT
@@ -1084,6 +1112,8 @@ U_BOOT_CMD(
 	"mmc list - lists available devices\n"
 	"mmc wp - power on write protect boot partitions\n"
 #if CONFIG_IS_ENABLED(MMC_HW_PARTITIONING)
+	"mmc maxhwpartsectors - shows the maximum number of 512-byte blocks usable for hardware partitioning\n"
+	"  Sets env var maxhwpartsectors on success.\n"
 	"mmc hwpartition <USER> <GP> <MODE> - does hardware partitioning\n"
 	"  arguments (sizes in 512-byte blocks):\n"
 	"   USER - <user> <enh> <start> <cnt> <wrrel> <{on|off}>\n"
-- 
2.17.1